Modeling Erosion Damage from Ephemeral Gullies
Perry July 11, 2008
Ephemeral gullies are common features on agricultural landscapes.
Concentrated water flows can erode cropland soils and carve out these small
drainage ditches, which then transport field runoff laden with eroded sediments
into nearby streams. In fact, these gullies may lead to soil losses that exceed
soil losses from sheet or rill erosion.
V. Alonso and agricultural engineer
L. Bingner work at the Agricultural
Research Service (ARS)
Sedimentation Laboratory in Oxford, Mississippi. They teamed up with
University at Buffalo scientists Lee
Gordon and Sean Bennett and Natural
Resources Conservation Service agricultural engineer Fred Theurer to
evaluate the effects of ephemeral gullies on erosion.
Ephemeral gullies are typically filled in throughout the year by
agricultural tillage practices. These tillage practices can remove or hide
gullies, but the channels often reappear in the same location after subsequent
rainstorms. These new channels easily erode the recently tilled fields and
start another cycle of gully development and topsoil reduction that can expand
across production fields.
The team developed a model to evaluate how tillage practices can
affect the formation and evolution of ephemeral gullies and subsequent soil
erosion rates. They used historical precipitation data, on-site field
observations, and recently developed watershed modeling technology to simulate
the effect of tillage practices on long-term ephemeral gully growth and
During a five-month growing season, tillage activities were simulated
using two alternatives: once-a-year conventional tillage and no-till management
practice. The collaborators applied the model to replicate a 10-year production
Their findings suggest that, on average, tillage in areas prone to
ephemeral gully erosion can produce significantly higher soil erosion rates
compared to those same regions under no-till management practices. Simulated
cumulative ephemeral gully soil erosion rates for the tilled fields were
anywhere from 240 percent to 460 percent higher than soil erosion rates from
the untilled fields.
The negative effects of tillage simulated in these watershed models
reinforce the advantages of using soil conservation technologies such as
no-till planting and other reduced tillage management practices.
ARS is a scientific research agency of the
U.S. Department of Agriculture.